Robert Kubica admits his season back in Formula 1 with Williams hasn't "paid back" the effort he undertook to make his return.

The Pole's comeback eight years after his horrific rally crash was one of the big stories at the start of the year, but the optimism quickly fizzled out with the British team stuck at the back of the grid throughout.

Not only that, but Kubica's performance compared to rookie teammate George Russell has also been underwhelming with the Briton considerably faster at most races despite Robert scoring the team's only point in Germany.

“I put a lot of energy [into coming back] and I think this year doesn’t really show it, I would say I’m not paid back by results and all other stuff,” he said via Motorsport Week.

“I think my effort was much more than what we were capable of achieving this year and I’m pretty confident that if I get in the right place in the right car I can still deliver."

Also Read:

• Williams admits Kubica exit unexpected, open-minded on 2020 replacement
• Kubica: Russell deserves a car at the front of the F1 grid
• Kubica: Achievement of F1 return being 'forgotten' due to Williams results

The most frustrating aspect of this season for Kubica is a feeling that he hasn't really had the chance to prove himself because of the poor pace of the Williams car.

“I still have not been racing since 2010 if you think about, it depends what you mean by racing," he claimed.

“But wheel to wheel [with a car] on the same level, I haven’t raced since 2010 because even if we get a chance of being around other cars like it happened on the last two races, we have two big disadvantages.

“I always said Formula 1 changed a lot depending on which row you are starting, it’s like different racing, we will see.

“I think in the end we are on time with talks and decisions, and the big part of the decision has been done, so now it’s a question of putting puzzles together and moving forward.”

As for his plans for 2020, Kubica has already been linked to an Audi seat at DTM while Haas is willing to offer a development driver role with some Friday practice appearances.

The 35-year-old though is yet to come to any kind of decision.

“I don’t think there is a lot of different championships that in the end, I might end up,” he admitted.

“If I tell you a couple more it’s easy to call or easy to think which possibly they might be, but as I said I think for now I’m honest, I’m concentrating on this year.

"I said that in August I would have a think and would make a decision.

“Sometimes it takes longer, sometimes a bit less time, but I think if you have on both sides of the table people who want to have an agreement and decide, but first of all you have to make your own decision and then move from there.”